#include<stdio.h>
#include<string.h>
int main()
{
    char c = 0, str[128] = { 0 };
    int a = 0, n = 0;
    while (scanf_s("%c", &c) != EOF)
    {
        a = (int)c;
        if (str[a] == 0 && a != 10)
            n++;
        str[a] = c;
    }
    printf("%d\n", n);
}